In attempting to find a solution to illegal immigration, it’s worth studying the root cause of the great majority of illegal entry into the United States. Individuals from poorer countries, mainly Mexico, want to work in the United States. Per-capita GDP in the US is roughly four times that in Mexico, so it’s easy to see why labor is trying to flow towards employment.

If illegal immigrants come to the US to find work, then the easiest way to stop illegal immigration is to remove that incentive. Federal and state governments can easily step up enforcement against businesses which hire undocumented workers, and can increase the fines to the point that it is uneconomical to hire illegal workers. Once the cost of hiring an undocumented worker exceeds that of hiring a documented worker, businesses will naturally follow the profit motive.

The Obama administration has accelerated business audits, quadrupling the previous administration’s efforts in that area. If employer audits were expanded and targeted at those sectors known to use illegal labor most heavily, demand for illegal labor would drop immediately. That in turn would decrease the number of would-be employees crossing into the US, as job opportunities thin out.

Effective enforcement of employment law, even against small businesses, would significantly reduce new illegal immigration. Once the flow of illegal immigrants is slowed from the current 500,000 per year to a trickle, an answer for how to deal with the 12 million among us today can be sought. But until businesses find that hiring illegal workers is unprofitable, the immutable laws of capitalism will cause laborers to find their way to the jobs.

I just saw a presentation by George Borjas, a Harvard economist specializing in immigration issues. His research seems to support the common-sense opinion on the effects of large-scale illegal immigration: it has some positive economic benefits, but it also redistributes wealth somewhat from poorer Americans to richer Americans. Since illegal immigrants compete for jobs mainly at the bottom of the economic scale, their arrival tends to increase the wealth of those who use labor (business owners and the upper-middle class), while decreasing the wages of unskilled Americans.

This is perhaps not very surprising, and refines my previous article’s view as to why illegal immigration has continued for so long: it has some benefits, and those benefits accrue primarily to middle and upper class Americans, who tend to vote at a higher rate than the poor. Only recently has the cultural backlash against Latinization reached a level necessary to unbalance the old equation and force immigration reform.

Though most of Lou Dobbs’ rhetoric is of little value, he is right on this: America cannot begin to have a rational immigration policy until it can control who immigrates.